Subject: Re: [linux-audio-dev] Problem setting recording level
From: Erik Steffl (esteffl_AT_pbi.net)
Date: Wed Apr 26 2000 - 18:30:12 EEST
I don't have direct solution, but I think that using external mixer
would be a good idea. there's part in oss docs that warns against
including more functionality into sound application then needed (kitchen
sink problem?), and I think they are right about it - the mixing should
be at least completely separated, better yet is to simply let user use
his own mixer (there's nothing wrong with providing your own default one
though).
erik
Stephane Letz wrote:
>
> Hi,
>
> I am trying to develop a full-duplex audio application on a system with an
> emu10k1 card installed using the OSS API. I need to mix sound played from
> files and sounds recorded and transformed in real-time.
>
> To set the record level, i use the following ioctl call :
>
> ioctl (mixer_device, SOUND_MIXER_WRITE(SOUND_MIXER_RECLEV)) to set the
> global recording level.
>
> My program then read sound buffers and play them back.
>
> To set the pcm level, i use the following ioctl call :
>
> ioctl (mixer_device, SOUND_MIXER_WRITE(SOUND_MIXER_PCM))
>
> To set the master level, i use the following ioctl call :
>
> ioctl (mixer_device, SOUND_MIXER_WRITE(SOUND_MIXER_VOLUME))
>
> The problem is that the level of real-time sound is very low when mixed
> with sound played from files.
> I tried to use Line in or Mic in without much difference (Mic in is
> better). Audio input (Line or Mic) as well as Line out (PCM or master)
> are stereo so i use (I hope correctly) the 256*vol_right+vol_left formula
> to compute the volume level.
>
> Any ideas?
>
> Stephane Letz
>
> Grame: Centre National de creation musicale
> 9, Rue du Garet
> 69001 Lyon
> Tel: 04-72-07-37-00
> Fax: 04-72-07-37-01
> Web: www.grame.fr
This archive was generated by hypermail 2b28 : Wed Apr 26 2000 - 19:44:36 EEST